Drive comparison
ST18000NM000J vs WD181KRYZ
Seagate Exos X18 18TB and Western Digital WD Gold 18TB, compared using published manufacturer specifications.
Seagate
Exos X18 18TB
ST18000NM000J
SATA 6 Gb/s · 3.5-inch
$694.00
Amazon US · New listing ↗ASIN B08JV6PP9B · as of Oct 27, 2026 13:33 UTC
Full specifications & all listings →
Western Digital
WD Gold 18TB
WD181KRYZ
SATA 6Gb/s · 3.5-inch
$599.00
Amazon US · Used / renewed listing ↗ASIN B09BHTP2HC · as of Oct 27, 2026 05:17 UTC
Full specifications & all listings →As an Amazon Associate I earn from qualifying purchases. Match the selected variant, condition and seller terms before ordering.
What differs between these models?
- Interface: ST18000NM000J lists SATA 6 Gb/s; WD181KRYZ lists SATA 6Gb/s.
- Cache (MB): ST18000NM000J lists 256; WD181KRYZ lists 512.
- Sustained transfer (up to MB/s): ST18000NM000J lists 270; WD181KRYZ lists 269.
A larger cache, higher RPM or higher advertised sequential speed alone does not establish which drive is better for your workload.
Specifications side by side
| Specification | ST18000NM000J | WD181KRYZ |
|---|---|---|
| Manufacturer | Seagate | Western Digital |
| Product family | Exos X18 | WD Gold |
| Model number | ST18000NM000J | WD181KRYZ |
| Capacity (TB) | 18 | 18 |
| RPM | 7200 | 7200 |
| Interface | SATA 6 Gb/s | SATA 6Gb/s |
| Recording | CMR | CMR |
| Cache (MB) | 256 | 512 |
| Form factor | 3.5-inch | 3.5-inch |
| Average idle power (W) | 5.3 | Not recorded |
| Power-on hours per year | 8760 | Not recorded |
| Manufacturer limited warranty | 5 years (eligible new drives) | 5 years (eligible new drives) |
| Sustained transfer (up to MB/s) | 270 | 269 |
| Workload rating (TB/year) | Not recorded | 550 |
| Logical sector size (bytes) | Not recorded | 512 |
| Physical sector size (bytes) | Not recorded | 4096 |
Compatibility and buying checks
- Compare new and renewed offers separately. The manufacturer specification does not guarantee the warranty or return policy of a marketplace seller.
Manufacturer sources
ST18000NM000J
Seagate Exos X18 manufacturer specifications ↗ · pages 2
CMR recording specification ↗ · checked 2026-10-02
Reviewed 2026-09-07. Published specifications; no independent benchmark or failure-rate claim.
WD181KRYZ
Western Digital WD Gold manufacturer datasheet ↗
Reviewed 2026-08-21. Published specifications; no independent benchmark or failure-rate claim.